Silver halide compositions stabilized with propiolic acid



United States Patent 3,499,764 SILVER HALIDE COMPOSITIONS STABILIZED WITH PROPIOLIC ACID Issei Iwai and Yasuo Yura, Tokyo, Yoshimi Kuwabara,

Koganei, Tokyo, and Sadao Suglta, Hannou, Japan, assignors to Sankyo Co., Ltd, and Konishiroku Photo Industry Co., Ltd., both of Tokyo, Japan N0 Drawing. Filed May 24, 1965, Ser. No. 458,433 Claims priority, application Japan, May 28, 1964, 39/ 30,179 Int. Cl. G03c 1/34 US. Cl. 96109 14 Claims ABSTRACT OF THE DISCLOSURE A light-sensitive, photographic silver halide composition containing propiolic acid as a stabilizer.

This invention relates to a stabilized photographic silver halide composition, and more particularly, it relates to a photographic element, e.g. photographic film, paper or plate, bearing on a support a photosensitive layer containing propiolic acid.

In the art it is well known that photographic compositions, when stored for a long period of time after their preparation, undergo a decrease in speed and the formation of an undesired fog. In order to prevent these adverse effects, a variety of stabilizers also have been proposed. Incorporation of the known stabilizers into the photographic composition, however, is disadvantageous because it usually causes a decrease in the speed of the film, and therefore the demand in the art has been directed toward developing a stabilizer which will prevent the formation of fog Without any adverse influence on photosensitivity.

It is accordingly one object of the present invention to provide a photographic silver halide composition which resists any undesired effect caused by storage over a long period of time.

Another object of the present invention is to provide a photographic element which is substantially immune to the formation of fog.

Other objects, features, capabilities and advantages which are comprehended by the invention will be apparent from the specification and claims which follow.

The above-mentioned and other objects can be attained by incorporating propiolic acid as a stabilizer into a photographic silver halide composition.

The Sheppard et a1. Australian Patent No. 101,708 is directed to a gelatino-silver halide emulsion containing a Weak organic acid, particularly a di-basic carboxylic acid, as a buffering agent to buffer the emulsion within a pH range of 5.5 to 9.5. However, the Australian patent indicates no reference to the use of such a strong acid as propiolic acid, especially for the purpose of fog prevention. In U.S.P. 2,367,549 and 2,380,280, W. I. Weyerts disclosed use of salts of certain aromatic carboxylic acids and salts of certain unsaturated fatty acids in photographic emulsions in order to achieve an increased speed in said emulsion. In this case, however, the emulsions usually suffer from an increase in fogging although their speed may be improved.

It has now been found that if propiolic acid is present in the photographic silver halide composition of the present invention, the said composition can be safely stored over a long period of time, without suffering a decrease in speed or formation of fog. In a typical embodiment of the present invention, propiolic acid may be incorporated into at least one of the layers of a photographic element, such layers including emulsion layers,

sub-layers, internal layers, protective layers and backing layers. Another advantage of the present invention is that where propiolic acid is added to a photographic emulsion during its ripening or digestion, it is possible to prevent fog formation and consequently to facilitate an increase of speed due to the ripening or digestion.

Incorporation of propiolic acid into a layer or layers of the photographic element of the present inve ntion can be made in the manner heretofore known in the art. For example, where propiolic acid is to be present in an emulsion layer of the said element, it is possible to add propiolic acid into the emulsion at any time just before, during or after the second ripening of said emulsion. Addition of propiolic acid at the stage after the second ripening of the emulsion is most preferred. Alternatively, propiolic acid may be added to a starting material for preparation of the emulsion, for example gelatine. The amount of propiolic acid to be added will vary depending on the type of emulsion, the degree of stabilization desired and the type of layer to which propiolic acid being added, but it usually is within the range of from 10 mg. to l g. per liter of the emulsion or coating solution. It is desirable to add this compound in solution dissolved in a suitable solvent, e.g. water, dilute sodium carbonate, methanol, ethanol, etc., if the addition is made to an emulsion.

The use of propiolic acid as a stabilizer does not adversely influence the sensitization of the photographic emulsion. Thus, propiolic acid can be added to a photographic emulsion sensitized by gold-, sulfuror other chemical sensitization or super-sensitization. Furthermore, propiolic acid sometimes can provide desirable effect to facilitate an increase of speed because the said compound will prevent increased fog which frequently accompanies the sensitization. It is, of course, true that a decrease of speed and increase of fog during storage of the emulsion also can be prevented by use of propiolic acid.

Still another advantage of the present invention is that fog and desensitization both of which frequently occur during the storage of a color photographic material containing large amounts of color formers in the emulsion can be effectively prevented by use of propiolic acid according to the present invention.

An emulsion to which propiolic acid has been added can be applied to a suitable support in the manner heretofore known in the art, e.g. coating or pouring. Suitable supports include films, papers and glass plates. Particularly suitable are films of the types such as cellulose esters, e.g. cellulose triacetate; polyesters obtained by the polycondensation of phthalic, isophthalic or terephthaic acid with a dihydric alcohol, e.g. polyethylene terephthalate, poly(cyclohexane-1,4 dimethylol)terephthalate, etc.; and polycarbonates including those obtained by the polycondensation of bis-phenyl A with carbonic acid.

The following examples describe certain ways in which the principle of the invention has been applied, but are not to be construed as limiting its scope.

EXAMPLE 1 A silver iodo-bromide emulsion useful for high speed negative and containing 3 mole percent of silver iodide is prepared according to a neutral process. This emulsion is subjected to a second ripening at a temperature of 60 C. for minutes. After the said ripening, the emulsion is divided to two portions, one of which is used for the preparation of a control film and the other of which is used in combination with propiolic acid in the amount of 70 mg. of propiolic acid per liter of emulsion. Each of the portions are used to prepare films which in turn are stored at 55 C. for 3 days and subsequently at 55 C. under a relative humidity of for 3 days. Samples 3 of these film coatings were then exposed in an intensityscale type sensitometer and developed for five minutes in a developer of the following formulation:

4 other portion in an amount of 10 mg. per liter of emulsion and the resulting mixture is subjected a second ripening at 60 C., while samples of each are collected at intervals of 20 min., 40 min., 60 min., 80 min., and 100 G a 5 min., and coated to film supports. The films obtained are Metol (p-methylaminophenol sulfate) 2.0 measured with respect to speed and fog according to the Sodium sulfite (anhydrous) 5 procedures described in Example 1. The results are set Hydroquinon 4.0 forth in Table III. Sodium carbonate (monohydrate) 7.0 Potassium bromide 0.75 TABLE In Water to make 1.0 liter. 40' 60' so 100' The developed samples were then stopped with dilute Cmm'olmm i fi i fififfffl 3g 33 32 X8 acetic acid, fixed, washed and dried. The results are set 55 flcidloaded lFielative Speed 0 3 0 8g 0 3g 120 forth in Table I. 0g

TABLE I Incubated at 55 0. Just after Incubated at 55 C. and 80% RH for preparation of for 3 days after 3 days after the film preparation preparation Relative Relative Relative speed Fog speed Fog speed Fog Control film 100 0. 03 40 0. 80 1. 20 Propiolic acid-loaded film 100 0.03 95 0. 05 85 0.07

In this test, photographic sensitivity which usually is an inverse number of the amount of light exposure to give an opitcal density of 0.1 above fog density, is expressed as relative speed to that of unstored control film. The data of Table I clearly indicates that the propiolic acid is useful for prevention of undesired fog.

EXAMPLE 2 The high speed negative emulsion used in Example 1 is subjected to a second ripening in the same manner as in Example 1. The treated emulsion is sensitized by the addition of dodecyl ethyleneoxide lauryl ether in an amount of 100 mg. per liter of the emulsion. The emulsion is divided into two portions, one of which is added with propiolic acid in the amount of 90 mg. per liter of emulsion. Comparative tests were conducted in the same manner as in Example 1. The results obtained are set forth in Table II.

In the above table, relative speed was defined with reference to the value of control having been ripened for 60 minutes as 100. As clearly shown in Table III, the speed of the films having been added with propiolic acid was found to be effectively increased relative to the time of ripening, with less tendency of fog, while the speed of these films was not so appreciably increased in comparison with the control during the early stages of the second ripening.

EXAMPLE 4 The high speed negative emulsion used in Example 1 is subjected to a second ripening at 60 C. for 75 minutes, and then, a solution containing 1-(4'-phenoxy-3-sulfophenyl)-3-heptadecyl-5-pyrazolone as a color former is added thereto. The resulting emulsion is coated onto a film base. Onto the surface of the resulting film, a 3% TABLE II Incubated at 0. Just after Incubated at 55 C. and 80% RH for preparation of for 3 days after 3 days aiter the film preparation preparation Relative Relative Relative speed Fog speed Fog speed Fog Control film 100 0. 05 40 1. 50 0 1. 80 Propiolie acid-loaded filn1 100 0.05 100 0. 10 80 0. 15

The data of Table II clearly indicates that photographic emulsions which have been sensitized can be safely stabilized by the addition of propiolic acid.

EXAMPLE 3 To the high speed negative emulsion used in Example 1, sodium thiosulfate is added as a sulfursensitizer in an amount of 2 mg. per liter of emulsion. The resulting emulsion is divided into two portions, one of which is used as a control and the other of which is used for the following test. Propiolic acid is added to the said TABLE IV Incubated at 55 Ineubated at 55 Just after 0. for 3 days 0. and RH preparation of after prepafor 3 days after the film ration preparation Relative Relative Relative speed Fog speed Fog speed Fog Control film 100 0. 06 40 0. 50 30 0. 65 Propiolic acid-loaded lilm 100 0.05 0. I5 80 0. l2

The data of Table IV clearly indicates that fog formation can be prevented in the presence of propiolic acid.

What we claim is:

1. A light-sensitive, photographic silver halide composition comprising a light-sensitive silver halide and propiolic acid as a stabilizer therefor.

2. A light-sensitive, photographic silver halide emulsion comprising gelatin having a light-sensitive silver halide dispersed therein and containing propiolic acid as a stablizer therefor.

3. A light-sensitive, photographic silver halide emulsion as claimed in claim 2; further comprising a member selected from the group consisting of sulfur-, goldand reductive sensitizers.

4. A light-sensitive, photographic silver halide emulsion as claimed in claim 2; further comprising a surface active agent.

5. A light-sensitive, photographic silver halide emulsion as claimed in claim 2; further comprising an optical sensitizer.

6. A light-sensitive, photographic silver halide emulsion as claimed in claim 2; further comprising a color former.

7. A photographic element comprising a support bearing thereon layers, at least one of which layers contains a photographic silver halide emulsion, and at least one of said layers having propiolic acid incorporated therein.

8. A photographic element as claimed in claim 7, wherein the propiolic acid is incorporated in at least one layer selected from the group consisting of emulsion layers, sub-layers, internal layers, protective layers and backing layers.

9. A photographic element as claimed in claim 7, wherein said support is a film mainly consisting of a polymeric material selected from the group consisting of cellulosic esters, polyesters and polycarbonates.

10. A photographic element as claimed in claim 9, wherein the polymeric material is cellulose triacetate.

11. A photographic element as claimed in claim 9, wherein the polymeric material is polyethylene terephthalate.

12. A photographic element as claimed in claim 9, wherein the polymeric material is the polycondensate of bis-phenol A and carbonic acid.

13. A light-sensitive, photographic emulsion as claimed in claim 2, wherein the propiolic acid is present in an amount corresponding to 10 mg. to 1 gm. per liter of emulsion.

14. A photographic element as claimed in claim 7, wherein the amount of propiolic acid incorporated in at least one of said layers corresponds to 10 mg. to 1 gm. per liter of the emulsion.

References Cited UNITED STATES PATENTS 3,212,900 10/1965 Oguchi et al. 96l09 I. TRAVIS BROWN, Primary Examiner J. R. EVERETT, Assistant Examiner 

